Trouble at Mayer Brown, one of Chicago's oldest law firms

In this Intelligence Report: trouble at the top of one of Chicago's oldest and most storied law firms, Mayer Brown. A former high ranking executive was arrested Thursday and charged with stealing nearly a million dollars in a fake billing scheme.

This is a difficult time for many law firms across Chicago. They are facing reduced billing, increased expenses and staff cutbacks. So this summer, when Mayer Brown managers discovered hundreds of thousands of dollars missing from their books, they were perplexed. When they traced it to a trusted high ranking executive, they were stunned.

In June, the firm fired David Tresch, its chief global information officer, after determining that Tresch had taken $850,000 in kickbacks from a company vendor. The unnamed Schaumburg company was supposed to provide Mayer Brown with office automation, website and database development, and general information technology

Mayer Brown, headquartered in the Loop, turned over the case to federal authorities. The FBI in Chicago opened a case, and Thursday Tresch was arrested and charged with mail fraud.

According to the criminal complaint unsealed Thursday, under Tresch's scheme to defraud, he approved vendor payments for work never actually done and then pocketed the payments made to the law firm, money he then used to fund personal purchases.

The FBI froze $210,000 they say he had stashed in bank accounts in Itasca, where he and his wife live, according to his resume, with their eight children.

Federal prosecutors have also seized several luxury purchases they say the 51-year-old Tresch made with money he had pilfered, including:

a 2011 Cadillac DTS

a new, full-size work van

an RV camper

and a mobile home.

Tresch worked at Mayer Brown since 2004, and according to the FBI, since that time he was also paid more than $1 million directly by the vendor in Schaumburg.

Tresch couldn't be reached Thursday.

The law firm has released a brief statement, saying, it is cooperating with federal authorities.